Elevator brake



Nov. 28, 1933. E. E. ARNOLD ET AL ELEVATOR BRAKE Filed Jan. 12, 1931 4 Sheets-Sheet l |NVENTOR5 Henry .D. James and E'dw/n E Erna/d B M fi TORN EY W/T/VE5555.

Nov. 28,- 1933.

E. E. ARNOLD El AL 1,936,780

ELEVATOR BRAKE Filed Jan. 12, 1931 4 Sheets-Sheet 3 76 MOT/M55555. INVENTORS, f; a jg; Henry D/nves 7 and EaW/h 5 HIV) 0/0.

. ATTORNEY Nov. 28, 1933. E. E. ARNOLD El AL ELEVATOR BRAKE Filed Jan. 12, 1931 4 Sheets-Sheet 4 Q y w a m; M N 0 fiJ m w w w 7 w/ FI E I w 6 p m A e W M, F Z a a n I a 6 N w 9 a 2W 8 o w Z I wk fFQ-Q.

W/ 771/55655. 6-2 ayzaz Patented 7 New 28,- 1933 UNITED STATES ELEVATOR BRAKE Edwin E. Arnold, Pittsburgh, and Henry .D,

James, Edgewcod, Pa., assignors to Westinghouse Electric and Manufacturing Company, a corporation of Pennsylvania Appiication January 12,1931. Serial. No. 508,059 v 13 Claims.

Our invention pertains to elevators and. more particularly to service brakes and. roller guides for use on elevator cars.

It has been the usual practice to operate elevator cars between guide rails which are lubricated to reduce the sliding friction between the guides on the car and the rails. The guide rails being lubricated, it has been difficult to provide a suitable service brake on the car for gripping the rails to accurately stop the car at the landings. t has been customary, therefore, to provide a brake on the elevator hoisting machine for service-brake purposes.

The machine brake, however, places the strain of stopping the car upon the bearings of the hoist drum and also strains the hoist cable each time a stop is to be made. Further, each time a load is discharged, or taken on, the accuracy of the landing of the elevator platform is impaired by the resilience or stretching of the hoist cables. The most desirable point at which to apply the braking force is directly to the car, but this has been previously considered impractical because the guide rails were lubricated.

The only braking device usually carried by the elevator car is a safety device which may be actuated by an overspeed governor to grip the rails and stop the car in the eventthat the hoist cables break, or some other emergency condition occurs. Such a device is effective as a brake only when it grips the rails with such a high unit-area pressure that the lubricant is scraped from the rails and the metal safety jaws bite directly into the guide rails.

When the usual safety device operates it stops the car abruptly and may gouge or scar the guide rails to such an extent that it will become welded directly thereto. Obviously, such a d vice is only intended for emergency use and would be entirely unsuitable for service use; It has been found possible, however, when operating an elevator car between dry guide rails, to

provide a service brake on the car having lined brake shoes which will grip the guide rails and bring the car to a smooth accurate stop.

It is accordingly an object of our invention to provide such guide means on an elevator car that the car maybe operated between dry guide rails.

It is also an object of our invention to 'provide a service brake which may be carried by the elevator car, and guide means such that the car may be operated between dry guide rails to facilitate the use of the service brake for stopping the car smoothly and: accurately at the landings.

It is a further object of our invention to provide a service brake which may be mounted on the car and means for controlling the application of the brake in accordance with the speed of the car, whereby the car may be brought smoothly to rest.

Another object of our invention is to provide a fluid-pressure controlled service brake mounted directly on an elevator car, and a hermetically sealed pressure generator and system for controlling the same.

The invention itself, however, both as to its organization and its method of operation, together with additional objects. and advantages thereof, will best be understood from the following description of specific. embodiments, when read in conjunction with the accompanying drawings, in which:

Figure l is a view, in side elevation, of an elevator car equipped in accordance with one form or our invention;

Fig. 2 is a plan View of the upper cross head and guide rails shown in Fig. 1; and

Fig. 3 is a View, in side elevation, of the upper cross head and guide rails shown in Fig. 2;

Fig. i is a plan view, in cross section, of a guide rail of T-shape and cooperating guide rollers associated therewith; and

Figs. 5 and 6 are, respectively, side and front elevational views of the structure shown in Fig. 4';

Fig. 7 is a plan view of the upper cross head of a car equipped in accordance with a modified form of our invention; i

Fig. 8 is a view, in side elevation, of the apparatus shown in Fig. '7; r

Fig. 9 is an enlarged detail view showing a section taken on a vertical plane through the center of the pressure-generating device of Figs; '7 and 8;

Fig. 10 is a cross-sectional View of a 'T guide rail showing a detail view of a braking device which may be utilized with the apparatus shownin Figs. 7 and 8.

Fig. 11 is a cross-sectional view of a channel guide rail showing guide rollers adapted to cooperate therewith; and

Figs. 1'2 and 13 are, respectively, side and front elevational views of the structure shown in-F'ig. ll.

, Referring to the drawings, the apparatus shown in Fig. 1 comprises an elevator car C suspended by hoist cables Ca for operation up and downa hatchway between guide rails 1- and 2 in the usual manner.

A safety braking device 5 is provided in the lower cross head of the car for preventing accidents by stopping the car upon the occurrence of emergency conditions. The safety device S may be of the conventional type wherein the jaws 3 and 4 are actuated to rail gripping positions by unreeling a safety cable from the safety drum.

In accordance with our invention, a service brake is provided on the car for stopping and holding the car at the landings and is mounted in associated relation to the upper cross head 6 thereof. As shown in Fig. 1, one of the stiles or vertical channel members 7 of the car is broken away and exposes the guide-rail-engaging members or brake shoes 8 associated with guide raill, and an associated pressure-responsive device 9 which controls the operation thereof. Similar devices are associated with the other guide rail 2.

Mounted in the cross head is a pressure tank 11 from which pressure is admitted, by an electromagnetic valve 12, to the pressure-responsive devices 9 to control the operation of the brakes. A pump is drivenby a motor, to maintain the pressure in the tank, which is automatically controlled by a pressure-responsive switch to maintain .a constant predetermined pressure in the tank. In order that the brakes maybe lined with brake-lining and. operate with maximum efflciency, roller guides 13 are provided on the car, and the guide rails are operated dry or unlubricated.

One form of braking device may be mounted on the elevator car is shown in detail in Figs. 2 and 3. Rail-engaging brake shoes 8 are mounted in the-stile '7 of the car adjacent to opposite sides of the guide rail 1 which is to be engaged thereby. Each rail-engaging brake shoe 8 is supported by an eccentric actuator shaft 16 which is pivotally mounted in the stile member. A lever arm 17 extends laterally from each eccentric shaft 16 toward the center of the car through suitable openings 18 in the stile member '7. The inner extremityof each lever arm 17 is connected to a toggle-link member 19. The inner extremities of. the toggle-link members 19 are pivotally connected to a pressure-responsive device 9, which may comprise a piston 21 to be operable in response to the fluid pressure admitted into a cylinder 22. When pressure is admitted to the cylinder, the piston 21 tends to straighten the toggle members 19 and thereby rotate the lever arms 1'7 and eccentric shafts 16 to withdraw the brake shoes 8 from the adjacent guide rail.

Passing freely through large openings in the lever arms 17 is a bolt 23, both ends of which are threaded. By placing a compression spring 24 on each end of the bolt, in concentric relation thereto, and compressing the springs 24 by suitably adjusting nuts 25 provided thereon, it is possible to provide the desired degree of force tending to urge the brake lever arms 17 together to apply the brake. In order to increase the effectiveness of the brakes, the shoes 8 may be lined with any suitable brake-lining material.

- To maintain suiiicient pressure in the pressure tank 11 for controlling the device, a pump 26 is driven by a motor 27 to pump fluid-from an exhaust tank 28 into the pressure tank. The motor is automatically controlled through a pressure-responsive switch 31, whereby a predetermined constant pressure is maintained in the tank 11. l

The admission of pressure to the brake cylin-' ders 22 is controlled by the electromagnetic valve 12 which is actuated by an electromagnet 32. The electromagnet 32 may be energized in any suitable manner, as by connecting it into the main car-switch control circuit (not shown). Hence, when the car switch (not shown) is centered, and the main control circuit is interrupted, the valve electromagnet 32 is deencrgized. The valve 12 then assumes the position shown in Fig. 3, wherein the brake cylinders 22 are connected to the exhaust tank 28, and the biasing springs 24 force the brake lever arms 17 together to apply the brakes.

When the car switch is moved to complete the control circuit for operating the car in either direction, the valve electromagnet 32 will be en ergized. The valve will then be raised to connect the brake cylinders 22 to the pressure tank 11, and the brake shoes 8 will be forced away frornthe guide rails in opposition to the biasing springs 24. The valve electromagnet 32 may be controlled by. the conventional elevator-brake circuit, if desired.

Roller guide devices 13 are provided on the car for guiding the movements of the car between the guide rails, which may be unlubricated. The specific structure of one form of roller guide, as shown in Figs. 4, 5 and 6, comprises a pair, of rollers 41 and 42 pivotally mounted on a horizontally disposed bracket 43. The brac'et 43 is pivotallysupported on a standard 44 which is attached to the car C and is disposed adjacent to. the guide rail 1, whereby a roller is disposed adjacent to each side of the stem thereof. In order to reduce the friction and noise or" operation to a minimum, the guide rollers 41 and 42 may be of some acoustic insulating material and may be mounted on roller bearings l5.

To prevent undue clearance between the guide rollers. and the stem of the guide rail, and to maintain them in continuous rolling engagement therewith, a biasing spring 46 is providedfor continuously biasing the bracket to rotate, in either direction, away from the horizontal posi tion.. The biasing spring 46 is concentrically disposed on a pivoted bolt 47 which passes through a large opening 48 in the bracket. By adjusting a nut 49 on the end of the bolt, the tension of the spring may be adjusted, as required, to eliminate the lateral oscillations of a car in any particular installation.

In order to prevent longitudinal oscillation of the car from one guide railtowardthe other, a longitudinally disposed guide roller49 is provided. The guide roller is journalled in the end of a bracket 51 which is pivotally mounted on a pin 52 extending through the standard attached to the car. The lever is biased, by a spring 53, concentrically disposed on a pivoted bolt 54, to hold the roller 49 in continuous rolling engagement with the edge of the guide rail, as the car passes up and down the hatchway. The biasing spring 53 is also adjustable, by screwing nuts 55 on the end of the bolt .54, whereby it may be adapted to the requirements of any particular installation.

Because the guide rails may be operated dry, the brake shoes may be lined, and the effectiveness thereof is very much increased. When brake shoes are unlined and the rails lubricated, it is not possiole to obtain any appreciable braking efiect until the brakes are applied with sufiicient force to bite into the rails.

In Figs. 7, 8, 9 and 10, a modified form of the invention is disclosed wherein the pressure-sup ply lneans and the pressure-responsive devices L reverse:

are hermetically sealed to prevent possibility of:- leakage. In thisform of our inyentionthebrake:

shoes 71 are shown controlled by eccentric-actuev ator shafts 72 which are pivotally supported above the upper cross-head, 6 0i, the car C,; al-.

though this specific arrangement isnot essential to our invention, Extending: laterally from each eccentric actuator shaft, is a lever arm 73. The,- lever arms '73 are so positioned that, they. are

spaced apart a greater distance thaninthe structure previously described.

Passing through relatively large, openings in he ner mi i of the lever arms fin-is. a.

75 and hold the brake shoes disengaged from the guide rails, an expansible pressure-responsive chamber or bellows 7'1 is in erposed between the e xpa si e ambe 7 s, flat rigid end pieces '78 but theside walls are of lever arms '73.

a resilient material which is corrugated to increase the expansibility of the chamber.

Instead of providing a pressure tank which is continuously charged, we prefer, in this form of our invention, to provide a hermetically sealed pressure generator 81 which generates fluidpressure only at the instant whenit is required. The

pressure generator, as shown in Fig. 9, consists of a metallic compressible fluid chamber of cylindrical bellows formation and means forcompressing the chamber when it is desired to actu ate the pressure-responsive devices. The upper end wall of the chamber is a rigid disc 82 provided with a depression in the center of the upper surface and a projection on the lower surface thereof. The side walls 83 of the chamber are of resilient material which is corrugated and secured around the lower edge to a rigid base structure 84. A spring 85 is compressibly secured between the base structure and the projection on theulower surface of the upper end plate 82 to maintain the depressible chamber in extended position.

The base structure Si is divided, by a partition 86, into a compression chamber 87 and anoutlet chamber 88, and, from the lower or outletchamber 88, supply pipes 89 extend to the various pressure-responsive devices to be actuated thereby. In order to regulate the rapidity of application and release of the brakes, two'adjustable spring-loaded check valves 91. and 92 are inter.- posed between the compression chamber 87 and the outlet chamber 88. One of the valves 91-is so positioned that it will only pass the fluid out, and the other valve 92 is so arranged that it will only pass it in.

Mounted above the bellows, is an electromagnet 95 which, when energized, actuates a core armature 96 to depress the bellows and actuate the pressure-responsive devices. The armature 96 may carry an extension rod 97 which passes through a passage 98 in the field structure 99 and the lower end of which is receivedby the depression in the upper surface of the endplate 82 of the bellows. The field structure andthe armature of the electromagnet are designed-toexert a force and a degree of-movement commensurate with the characteristics of .thepressure-generatns.v and he! pressurer cspcnsive bellows: to: be a tnatedther by- I The pressureegener-ating sylphon; andaotuatin electromagnet may be. mounted on either side of the hoist cablesCa passing, through, the upper cross head of. the car, or at any other convenient. position. The electromagnet 95 maybe energized, by theusualelevator brakecircuit or by any other circuit desired. In order ,to reduce the degree of gization: of, the electromagnet 9,5..to bring, the carto-a smoothv stop, a resistor. l0lgmay-be C0117.

nected into. the'energ-izing circuit 102,103. and:

associated with suitable speed-responsive means 104 forcutting sections ofrthe resistor into the circuit as the car speed diminishes, asindicated in. Fig. 8.

In order to provide spacefor mounting the eccentricactuator-shafts 72 and levers 73abovethe upper cross head 60f the car, the guide rollers are so mounted that they areelevated a certain. distance therefrom.

In Figs. 11,12 and13 is shown amodifiedrollerguide device whichis adapted to cooperate with;

channel guide rails. This. device comprises a lever 111 pivotally mounted. on the car adjacent tothe channel guide rail 112 and a pair of guide rollers 113 and 114 mounted. on .the lever 111 in such positions thereon that they engage the inner sur faces of the flangesof. the rail. The rollers 113 and 114 are journalled on the lever 111 at points on opposite sides of the lever pivot. A biasing spring 116 is supported in. concentric relation. on a pivoted bolt 117 which extends through a.

large opening 118 inone end of the lever 111 and tends to rotate the lever- 111 toward a horizontal position, thereby diverting the rollers 113 and llito maintain continuous rolling engagement with the flanges of the guide rail. By means. of. nuts 119 threaded on the end of the bolt 117, the spring 116 may be adjusted to apply the degree of tension required to prevent lateral oscillations of the car for any particular installation.

To prevent longitudinal oscillations of the car back and forth between the guide rails, a roller 121 is mounted for rotation in a longitudinal plane on the end. of a lever 122.. The lever 122 is pivotally mounted adjacent to-the web of the rail, and a biasing spring 123 continuously reacts, between a fixed stop 124'and a pivoted bolt 125, to hold the roller 121 against theweb of the channel guide rail. as the car passes up and down the'hatchway. The end of bolt 125 is threaded to receive nuts 126 for adjusting the tension on the biasing spring, and thedevice may thereby be adjusted to suit the requirements of any particular installation.

' It will 'be understood that we have provided a service brake which may be carried by the elevator car, and such guide means that the car "may be operated between dry guide rails and the rail-engaging brake shoes may be lined to increase the effectiveness thereof.

Although we have shown and described certain specific embodiments of our invention, we are fully aware that many modifications thereof are 1 possible. Our invention, therefore, is not to be restricted except as necessitated by the prior art and by the spirit of the appended claims.

We claim as our invention:

1. In combination, an elevator car, guide rails forcontrolling-themovements of thejawaanda 1 springs biasing said brake shoes to rail-gripping.

position, hermetically sealed elements responsive to fluid pressure for holding the brake shoes disengaged from the rails in opposition to the biasing springs, and a hermetically sealed pressure-generating bellows for actuating the pressure-respon sive elements.

3. In combination, an elevator car, guide rails for guiding the car as it travels up and down the hatchway, a braking device mounted on the car comprising rail-gripping shoes, springs biasing said shoes to rail-gripping position to grip the rails and retard the car, hermetically sealed expansible chambers positioned adjacent to the rail-gripping shoes for holding them away from the rails in opposition to the biasing springs, a

compressible hermetically sealed chamber con-r nected with said expansible chambers for applying fluid pressure thereto, means for applying a compressing force to said compressible chamber to expand the expansible chambers and release the brakes, and spring-biased check valves interposed in said connections for egulating the speed of application and release of said brakes.

4. In combination, an elevator car, guide rails for guiding the car as it travels up and down the hatchway, a braking device mounted on the car comprising rail-gripping shoes, springs biasing .said shoes to rail-grippingposition to grip the rails and retard the car, hermetically sealed expansible chambers positioned adjacent to the rail-gripping shoes for holding them away from the rails in opposition to the biasing springs, a

compressible hermetically sealed chamber connected to said expansible chambers for applying fluid pressure thereto, means for applying a com pressing force to said compressible chamberto expand the expansible chambers and release the brakes, and means for automatically varying the applied force in accordance with the speed of the car, whereby the brakes are actuated to bring the car to a smooth stop.

5. In a roller guide for guiding an elevator car in its movements up and down the hatchway between the guide rails comprising a bracket adapted to be mounted on each side of the car for pivotal movement about a horizontal 'aXis of rotation 6. A roller guide for guiding an elevator car in its movements up and down the hatchway between T guide rails comprising a bracket adapted to be mounted on either side ofthe car for pivotal movement about a horizontal axis of rotation in alignment with the stem of the rail, a rail-engaging roller journalled on each end of the bracket for engagement ,with opposite sides of the stem of the guide rail, a biasing means for imparting a movement of rotation to said bracket, whereby the rollers are urged to continuous rolling engagement with the opposite sides of the stems of the guide rails, additional brackets pivotally mounted on each side of the car adjacent a g'ui'derail, a guide roller' carried by each bracket, andbiasing means for rocking each bracket toward the rail, whereby the roller is urged into continuous rolling engagement with the edge of the stem of the guide rail.

7. In a roller guide for guiding an elevator car in its movements up and down a hatchway between channel guide rails, guide rollers on the car engaging the inside surfaces of the channel flanges to prevent the car moving laterally away from between the rails, and guide rollers mounted on the car in engaging relation to the webs of the channel guide rails to prevent longitudinal movement'of the car toward one rail and away from the other.

8. In a roller guide for guiding an elevator car in its movements up and down the hatchway between channel guide rails, a lever pivotally mounted on each side of the car adjacent to each channel guide rail, guide rollers mounted on the levers in such positions thereon that they engage the inner surfaces of the flanges of the channel guide rails, and biasing means tending to rotate the levers toward a horizontal position, thereby extending the rollers laterally to maintain continuous rolling engagement with the flanges of the guide rails. i

' 9. Ina roller guide for guiding an elevator car in its movements up and down the hatchway between channelguide rails, a lever pivotally mounted on each side of the car adjacent to each channel guide rail, guide rollers mounted on the levers in such positions thereon that they engage the inner surfaces of the flanges of the channel guide rails, biasing means tending to rotate the levers toward a horizontal position, thereby extending the rollers laterally to maintain continuous rolling engagement with the flanges of the guide rails, a pivoted bracket mounted on each side of the car adjacent to each guide rail, a guide roller mounted on the end of each bracket, and biasing means for swinging each bracket toward the web of the adjacent channel guide rail, whereby the associated roller rolls along the web of the railas the car passes up and down the hatchway.

10. A braking device for retarding elevator cars operable between guide rails comprising a pair of eccentric-actuating shafts pivotally mounted on the car on opposite sides of each guide rail, a lever arm extending laterally from each shaft, brake shoes associated with said shafts, and meansfor applying equalized forces to the lever arms for rotating the shafts in a proper direction to cause the brake shoes to recede from the guide rails or'to approach and engage the guide rails, as desired.

. 11. .A braking device'for elevatorcars operating between guide rails comprising a pair of rail engaging brake shoes mounted on the car and disposed on opposite sides of each guide rail, a pivotally mounted eccentric-actuating. shaft associated with eachbrake shoe, a lever arm extending laterally from each eccentric-actuating shaft, biasing means urging the levers toge' her for rotating the eccentric-actuating shafts to force the brake shoes into engaging relation with the guide rails, and expansible pressure-responsive chambers interposed between the lever arms to force the lever arms apart in opposition to the biasing springs to release the brake.

12. A braking device for retarding elevator cars operable between guide rails comprising a pair of eccentric-actuating shafts pivotally guide rail, a lever arm extending laterally from each shaft, biasing means associated with the lever arms for applying equalized arms for applying equalized forces tending to rotate the eccentric-actuating shafts toward the guide rails, hermetically sealed expansiole bellows associated with the lever arms for opposing the biasing means to prevent the applications of the brake thereby, and hermetically sealed pressuregenerating means connected to said bellows for supplying a predetermined pressure thereto, as desired.

13. A braking device for elevator cars operating between guide rails comprising a pair of railengaging brake shoes mounted on the car and disposed on opposite sides of each guide rail, 9. 

